Hypersonic HAWC missile flies, but details are kept hidden • Hacker News Board

Re: Hypersonic HAWC missile flies, but details are kept hidden

#121

Post by jasonwatkinspdx » Wed, Sep 29, 2021, 2:35 AM UTC

tptacek wrote: post #108

jasonwatkinspdx wrote: post #91

Earlier quoted context omitted.

Eh, you see a headline every so often alleging this but they're pretty far off the mark. CSGs are defended by the entire system operating in layers. During conflict conditions they'll have airborne early warning radar flying to see threats coming a long way out. There's usually at least 4 AEGIS equipped ships. The carrier air wing will be doing patrols and intercepting threats at great distance. The carrier itself wi…

Has the belief that these platforms are survivable ever been tested in a meaningful scenario (ie, a conflict between two carrier-group-capable adversaries)? I get that the Navy does a lot of stuff to mitigate this threat, but it's a hell of a threat to mitigate.

In terms of actual conflict no. There's been no large scale naval conflict since WW2. The closest is the Falklands war, which did show anti ship cruise missiles can be effective, but is not a good basis for generalization.

The Navy does do large scale wargaming exercises of course, though any of the interesting details aren't going to be public so that doesn't really help shed any light on it.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#122

Post by nautilius » Wed, Sep 29, 2021, 2:37 AM UTC

SonicScrub wrote: post #113

fnord77 wrote: post #94

would a MARV-tipped ICBM be able to reach a target faster than flying straight at it at Mach 5? I was looking for MARV reentry velocities, couldn't find any numbers. A regular ballistic missile hits mach 20+ on reentry but I don't know if it maintains that speed all the way to the target.

From my understanding, the primary benefit of the Hypersonic Missile over the ICBM is not the speed of payload delivery, but the amount of warning given to the target. An ICBM needs to ascend 100s of kms, thus enabling it to be detected by very far away radar systems. Those same radar systems that would be over the horizon at the lower altitudes within the atmosphere. Launching an ICBM almost immediately announces to…

And the maneuverability - if you just adjust the course slightly ten seconds before impact, at these speeds, that’s a big difference. Ballistic mostly just falls down, i.e. you know what it will hit when you observe the launch (somewhat simplified).

Re: Hypersonic HAWC missile flies, but details are kept hidden

#123

Post by gonzo41 » Wed, Sep 29, 2021, 2:50 AM UTC

lumost wrote: post #114

mzs wrote: post #25

Earlier quoted context omitted.

Though it means mach 5+ in terms of weapons systems it indicates a capability for a long highly maneuverable period at those speeds. https://www.gao.gov/blog/faster-speed-sound-u.s.-efforts-dev...

It's worth noting that at these speeds a "long" period need only be ~1 hour to reach a target from launch. A flight from Hawaii to Taipei would be 1.3 hours at Mach 5, and 54 minutes at Mach 7. These weapons represent an ability for both the US and China to conventionally intervene from their mainlands to any location within the Pacific.

It's an expensive asset though. You'd think planners would only considered large missiles like this for nuclear weapons. There's got to be a risk that using a conventional warhead would get mistaken for a nuclear attack. I think hypersonic weapons will be largely stranded assets.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#124

Post by ashtonkem » Wed, Sep 29, 2021, 3:02 AM UTC

nautilius wrote: post #120

ashtonkem wrote: post #117

Earlier quoted context omitted.

Fun, unrleated fact. Transsonic is very bad for rifle accuracy, as it tends to be somewhat unpredictable. For most rifle calibers this isn't a big deal, because they spend their entire flight time in the supersonic flight regime. But for 22lr, this is an issue because even the fastest 22lr around is going to be subsonic within 100 yards or so for reasons[0]. The result is a shot that’s laser accurate until 100 yards…

What kind of pressures do you have in a barrel?

Lots! The maximum chamber pressure allowable for a given civilian caliber is set by one of two regulatory bodies, SAAMI (US) or CIP (EU). In some countries firearm barrels will be tested (“proofed”) at 125% of set pressure to ensure consumer safety, and then stamped with a proof house specific mark. My understanding is that the US doesn’t require this, but any imported barrels will be stamped.

Specifically CIP sets the maximum pressure of 22lr at 24,646 psi. An extremely high number considering, but pretty pedestrian compared to other cartridges. For example NATO sets a maximum pressure of 62,366 psi for its primary rifle caliber, 5.56x45mm. It’s genuinely amazing that rifle barrels don’t regularly explode, to be honest.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#125

Post by lumost » Wed, Sep 29, 2021, 3:12 AM UTC

gonzo41 wrote: post #123

lumost wrote: post #114

Earlier quoted context omitted.

It's worth noting that at these speeds a "long" period need only be ~1 hour to reach a target from launch. A flight from Hawaii to Taipei would be 1.3 hours at Mach 5, and 54 minutes at Mach 7. These weapons represent an ability for both the US and China to conventionally intervene from their mainlands to any location within the Pacific.

It's an expensive asset though. You'd think planners would only considered large missiles like this for nuclear weapons. There's got to be a risk that using a conventional warhead would get mistaken for a nuclear attack. I think hypersonic weapons will be largely stranded assets.

A ballistic missile at Mach 25 is an easily detected threat that the other side wouldn't be able to determine was inbound for the mainland or some fleet off the coast. Odds are inbound hypersonic weapon would avoid detection until it's directly within radar range.

This would likely mean the weapon hits its non-mainland target prior to the other side taking notice for a retaliatory strike. In the event the other side did notice - it's likely they wouldn't treat it as a nuclear incursion unless the weapon was heading inland towards missile silos or other infrastructure that would motivate a nuclear retaliation.

To your point on stranded assets - these weapons make performing any large military action in the pacific much riskier with greater probability for missteps or stalemates. Assuming a cost of 20-100 million dollars per missile I wouldn't be surprised if they are cost competitive with high risk carrier based F-35 operations in a hypothetical Pacific conflict. It's probably cheaper to stock pile such missiles than maintain additional carrier strike groups for the sole task of participating in a great power conflict.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#126

Post by anovikov » Wed, Sep 29, 2021, 3:33 AM UTC

x86_64Ubuntu wrote: post #19

What does hypersonic mean? I thought all missiles were largely supersonic, except for maybe cruise missiles.

For a powered flight, it refers to the state where combustion in the engine happens at supersonic speeds (for a "normal" supersonic planes like fighters, it's subsonic because speed of sound in a heated air is much higher).

For an unpowered flight, it is a rather meaningless term, but normally refers to maneuvering warheads on ballistic missiles

Re: Hypersonic HAWC missile flies, but details are kept hidden

#127

Post by R0b0t1 » Wed, Sep 29, 2021, 3:40 AM UTC

credit_guy wrote: post #102

nielsbot wrote: post #79

Earlier quoted context omitted.

OMG "The Pentagon’s FY2022 budget request for hypersonic research is $3.8 billion"

Is this a lot? Missiles are quite expensive in general. $3.8 BN is not the budget for this single program, but for several, 8 per this source [1] (although, now it might be 1 or 2 less). For this particular weapon, a somewhat similar weapon I can think of is the European Meteor [2], which is ramjet (rather than scramjet) powered, and reaches Mach 4, rather than over Mach 5 as this one is supposed to do. Meteor comes…

> it's like destroying 10 Ferraris.

But, like, really cool.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#128

Post by throwawaylinux » Wed, Sep 29, 2021, 3:45 AM UTC

lumost wrote: post #114

mzs wrote: post #25

Earlier quoted context omitted.

Though it means mach 5+ in terms of weapons systems it indicates a capability for a long highly maneuverable period at those speeds. https://www.gao.gov/blog/faster-speed-sound-u.s.-efforts-dev...

It's worth noting that at these speeds a "long" period need only be ~1 hour to reach a target from launch. A flight from Hawaii to Taipei would be 1.3 hours at Mach 5, and 54 minutes at Mach 7. These weapons represent an ability for both the US and China to conventionally intervene from their mainlands to any location within the Pacific.

> It's worth noting that at these speeds a "long" period need only be ~1 hour to reach a target from launch. A flight from Hawaii to Taipei would be 1.3 hours at Mach 5, and 54 minutes at Mach 7.

> These weapons represent an ability for both the US and China to conventionally intervene from their mainlands to any location within the Pacific.

Is that the kind of range these have? Almost 9,000 miles from LA to the South Western most corner of the Pacific. If you meant the North Pacific then even the western edge of the US to the yellow sea is over 5,500 miles.

Ballistic missiles of course have these kind of ranges and can carry conventional payloads.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#129

Post by sandworm101 » Wed, Sep 29, 2021, 3:47 AM UTC

anovikov wrote: post #126

x86_64Ubuntu wrote: post #19

What does hypersonic mean? I thought all missiles were largely supersonic, except for maybe cruise missiles.

For a powered flight, it refers to the state where combustion in the engine happens at supersonic speeds (for a "normal" supersonic planes like fighters, it's subsonic because speed of sound in a heated air is much higher). For an unpowered flight, it is a rather meaningless term, but normally refers to maneuvering warheads on ballistic missiles

That is the difference between ramjets and scramjets, not necessarily the definition of hypersonic. And some "hypersonic" missiles don't breath air but rather conventional rocket motors to muscle their way to higher speeds.

The oldest definition of hypersonic I have heard is those speeds where compression heating of the atmosphere ahead of the craft generates plasma. A space capsule on reentry hits such speeds, causing the classic radio blackout. So hypersonic aircraft are those that must deal with plasma-related issues that are irrelevant to slower supersonic aircraft.

Re: Hypersonic HAWC missile flies, but details are kept hidden

#130

Post by nradov » Wed, Sep 29, 2021, 3:49 AM UTC

dirtyid wrote: post #71

echelon wrote: post #53

Earlier quoted context omitted.

The PRC is developing a blue water navy and is heavily ramping up on carrier shipbuilding. It makes sense that the US would want to build similar, land-based defensive strategies as a deterrent.

>The Air Force has said it plans to pursue both the ARRW and the Hypersonic Attack Cruise Missile (HACM), as initial and future hypersonic attack capabilities, respectively. These are offensive standoff weapons launched from air designed to hit time sensitive targets. The question is really what targets, like I said, spending the money on 3000 JASSMs is already enough to sink every major PLAN combatants with room to…

It's for prompt global strike against high value, time-sensitive targets when there are no platforms capable of launching JASSMs (or similar weapons) within range.